A system for long-reach lightwave data transmission through optical fiber is disclosed in U.S. patent application Ser. No. 10/289,944, filed Nov. 6, 2002 by Daniel Mahgerefteh et al. for POWER SOURCE FOR A DISPERSION COMPENSATION FIBER OPTIC SYSTEM, which patent application is hereby incorporated herein by reference. Azna LLC of Wilmington, Mass. sometimes refers to the transmitter apparatus of this patent application as a Chirp Managed Laser (CML™). In this system, a frequency modulated (FM) source is followed by an optical discriminator, also sometimes referred to as optical spectrum reshaper (OSR), which converts frequency modulation into a substantially amplitude modulated (AM) signal and partially compensates for the dispersion in the transmission fiber.
The optical spectrum reshaper (OSR) can be formed by any optical element that has a wavelength-dependent transmission function. The OSR can be adapted to convert frequency modulation to amplitude modulation. Significantly, the OSR can also be adapted to convert amplitude modulation to frequency modulation. The means and advantages of converting amplitude modulation to frequency modulation with an OSR has been described U.S. Provisional Patent Application Ser. No. 60/569,769, filed May 10, 2004 by Daniel Mahgerefteh et al. for FLAT CHIRP INDUCED BY AN OPTICAL FILTER EDGE which patent application is hereby incorporated herein by reference.
The phase imparted by the OSR may also be used to compensate for at least a portion of the dispersion of the transmission fiber, as disclosed in U.S. patent application Ser. No. 10/289,944, filed Nov. 6, 2002 by Daniel Mahgerefteh et al. for POWER SOURCE FOR A DISPERSION COMPENSATION FIBER OPTIC SYSTEM.
A variety of optical spectrum reshapers (OSRs), sometimes referred to as optical discriminators in one or more of the above-identified patent applications, are disclosed in the aforementioned U.S. patent application Ser. No. 10/289,944.
Semiconductor material growth make it possible to integrate various optical components, leading to the smaller size, ease of mass production and low manufacturing cost that the electronics industry now enjoys. This is one goal of planar light wave technology, which seeks to replace bulk optical elements used in a transmitter, for example, by waveguide-based devices.
It is, therefore, an object of the present invention to make a CML™ laser source which can be integrated. The CML™ laser source comprises a frequency modulated source such as a distributed feedback laser chip (DFB) and an OSR.